Quarantine Maths Simple Quiz

Explanation
All angles in a triangle add up to 180 degrees.

Explanation
The Pythagorean theorem states that in a right-angled triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. This theorem does not hold true for all triangles, as it specifically applies to right-angled triangles. In an isosceles triangle, two sides are equal in length, but the theorem does not apply unless the triangle is also right-angled. Therefore, the correct answer is "Right angled triangle."

Explanation
A sphere is a three-dimensional geometric shape that is perfectly round and symmetrical. It is formed by all the points in space that are equidistant from a fixed center point. Unlike a circle, which is a two-dimensional shape, a sphere exists in three dimensions and has volume. Therefore, the correct answer for this question is sphere.

Explanation
An obtuse angle is the biggest angle among the three options. It measures more than 90 degrees but less than 180 degrees. A right angle measures exactly 90 degrees, while an acute angle measures less than 90 degrees. Therefore, the biggest angle is an obtuse angle.

Explanation
A polygon is defined as a closed figure with straight lines. Since the given figure is closed and has straight lines, it meets the criteria of being a polygon. Therefore, the correct answer is "Yes".

Explanation
The given statement is true. The formula C=2πr represents the circumference of a circle, where C is the circumference and r is the radius of the circle. The formula states that the circumference is equal to twice the product of π (pi) and the radius. This is a well-known formula in geometry and is used to calculate the distance around a circle. Therefore, the answer is true.